The evolution of genome size and distinct distribution patterns of rDNA in Phalaenopsis (Orchidaceae).

Bibliographic Details
Title: The evolution of genome size and distinct distribution patterns of rDNA in Phalaenopsis (Orchidaceae).
Authors: LEE, YUNG-I., MEI-CHU CHUNG, HAO-CHIH KUO, CHUN-NENG WANG, YI-CHING LEE, CHIEN-YU LIN, HONG JIANG, CHIH-HSIN YEH
Source: Botanical Journal of the Linnean Society; Sep2017, Vol. 185 Issue 1, p65-80, 16p
Subject Terms: PHALAENOPSIS, PHYLOGENY, RECOMBINANT DNA, GENOMES, CHROMOSOMES
Abstract: Phalaenopsis is a horticulturally important genus of c. 63 spp. native to Southeast Asia. Aiming to understand the genome differentiation and phylogenetic relationships in diploid Phalaenopsis spp., we investigated the nuclear DNA content by flow cytometry karyomorphology and mapped rDNA loci by fluorescence in situ hybridization to address genome differentiation. Most species have a chromosome complement of 2n = 38 (but have different karyotype compositions). Chromosome reduction is only observed in Phalaenopsis section Aphyllae (2n = 34 and 36). The genome sizes differ 6.3-fold, from 1C = 1.39 to 8.74 pg. Reconstruction of genome size indicates the genome size for the most recent common ancestor of Phalaenopsis subgenus Parishianae to be 3.92 pg/1C and for subgenus Phalaenopsis to be 2.42 pg/1C. The 45S rDNA sites are polymorphic and correlate positively with genome size, but 5S rDNA sites do not. Our results suggest independent evolutionary processes of genome size increase or decrease in each Phalaenopsis lineage. The polymorphism in the number of rDNA loci reveals that complex chromosomal rearrangements, e.g. gain or loss of repetitive DNA or chromosomes, inversion and/or transposition events, may have contributed to create the various karyotypes observed in Phalaenopsis spp. [ABSTRACT FROM AUTHOR]
Copyright of Botanical Journal of the Linnean Society is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Complementary Index
More Details
ISSN:00244074
DOI:10.1093/botlinnean/box049
Published in:Botanical Journal of the Linnean Society
Language:English